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Update Protection against Microsoft IIS WebDAV Extension URL Decoding Security Bypass Vulnerability (MS09-020)

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Check Point Reference: CPAI-2009-130
Date Published:
Preemptive Since:
Severity:
Last Updated:
Source: Microsoft Security Bulletin MS09-020
Industry Reference(s): CVE-2009-1535
Protection Provided by: Security Gateway
  • R70
VPN-1
  • NGX R65
  • NGX R62
VSX
  • NGX R65
InterSpect
  • NGX
IPS-1
  • IPS-1
  • IPS-1 NGX R65
Who is Vulnerable?
Microsoft Internet Information Services 5.0
Microsoft Internet Information Services 5.1
Microsoft Internet Information Services 6.0
Vulnerability Description
An elevation of privilege vulnerability has been reported in the Microsoft Windows WebDAV extension for IIS. Web Distributed Authoring and Versioning (WebDAV) is a set of extensions for HTTP that allow clients to publish, lock, and manage resources on the Web. A remote attacker may exploit this vulnerability to gain unauthorized access to protected resources.
Update/Patch Available
Apply patches:
Microsoft Security Bulletin MS09-020
Vulnerability Details
The vulnerability is due to an error in the Microsoft Windows IIS WebDAV extension that fails to properly decode certain requested URLs. This causes WebDAV to apply an incorrect configuration when handling the request. If the applied configuration allows anonymous access, a malicious request can bypass authentication. To trigger this issue, an attacker may create a specially crafted HTTP request and send it to a website that requires authentication. Successful exploitation may allow the attacker to gain unauthorized access to protected resources.

Protection Overview
This protection will detect and block WebDAV requests attempting to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway/VPN-1 product to the latest SmartDefense/IPS update. For information on how to update SmartDefense/IPS, go to SBP-2006-05, Protection tab and select the version of your choice.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway R70

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > Web Servers > IIS.
2. In the right pane, double-click the Microsoft IIS WebDAV Extension URL Decoding Security Bypass protection.
3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Web Server Enforcement Violation
Attack Information: Microsoft IIS WebDAV extension URL decoding security bypass

VPN-1 NGX R65 & R62

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > Web Servers > IIS.
2. Select the following:

Microsoft IIS WebDAV Extension URL Decoding Security Bypass

3. In the configuration pane, under Settings > Mode, check Active.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Web Server Enforcement Violation
Attack Information: Microsoft IIS WebDAV extension URL decoding security bypass

VPN-1 VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > Web Servers > IIS.
2. Select the following:

Microsoft IIS WebDAV Extension URL Decoding Security Bypass

3. In the configuration pane, under Settings > Mode, check Active.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Web Server Enforcement Violation
Attack Information: Microsoft IIS WebDAV extension URL decoding security bypass

InterSpect NGX

How Can I Protect My Network?
1. In the left pane, select Profiles > Default Protection and select the SmartDefense page of the profile.
2. In the SmartDefense tree, click Application Intelligence > Web Servers > IIS.
2. Select the following:

Microsoft IIS WebDAV Extension URL Decoding Security Bypass

4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Web Server Enforcement Violation
Attack Information: Microsoft IIS WebDAV extension URL decoding security bypass

IPS-1 & IPS-1 NGX R65

How Can I Protect My Network?
1. In the IPS-1 Policy Manager, click on the Protection tab.
2. In the Protection tree, click Web Intelligence > WWW 2, and select the Strict Compliance protection group.
3. Click URL contains UTF-8 encoding which is not fully normalized - IPS-1 NGX R65 only.
4. In the configuration pane, under Settings, check Active.
5. Click on Install Policy.

How Do I Know if My Network is Under Attack?
Upon attack, the following entries will be logged:

Alert Name: HTTP Compliance
Description: URL contains UTF-8 encoding which is not fully normalized